Mechanical movement.



PATENTED JULY 14, 1908.

N 0 T S N H nu .J T R MECHANICAL MOVEMENT. APPLIOATION FILED JULY 27,1905. RENEWED NOV-21. 1907.

2 BHBETSSHEET 1.

In Me. W500 1 311754 715 (021. 5 flttaeree 5 I 'wTl/esses No. 893,246.PATENTED JULY 14, 1908.

R. T. JOHNSTON.

MECHANICAL MOVEMENT. APPLIOATION'IILED JULY 27,1905. RENEWED NOV.21.1907. Y

' mums-$113M z.

UNITED STATES PATENT OFFICE. ROBERT T. JOHNSTON, OF TAUNTON,MASSACHUSETTS, ASSIGNOR TO THE CAMPBELL PRINT- ING PRESS & MANUFACTURINGCOMPANY, OF TAUNTON, MASSACHUSETTS.

MECHANICAL MOVEMENT.

Patented July 14, 1908.

Renewed November 21, 1907. Serial No. 403,189.

for reciprocating the beds of printing presses,

which consists of a main driving mechanism and a reversing mechanism.

The particular object of the invention is to improve the main drivingmechanism which gives the bed its constant speed backward and forwardmovements. The main driving mechanism commonly employed for this purposeconsists of two racks attached to the,

bed and a gear disposed between said racks which gear is either moved upand down or slid axially to engage alternately with said racks. j Y

When a rising and falling -movement is imparted to the driving gear, astructure is provided which is objectionable for the reason that thegear cannot be rigidly supported and which is apt to have lost motion;while when the gear is slid axially it must drive one rack atconsiderable distance from its support. I overcome these objections bysetting the racks a distance a art a little greater than the diameter'ofthe rivin gear and in providing two intermediates w ich are slidlaterally-to engage the racks alternately.

The gear disposed between the racks is made wide-faced so that eachintermediate is in mesh whether it is operating or not. Theintermediates can he slid on rigid studs or bearings and as eachintermediate only comes into operation when it is in the plane of theracks, the parts will be rigidly supported when in operation.

The best form now known to me for practicing the invention is shown inthe accom panying two sheets of drawings in which,

Figure 1 is a side elevation partly in section illustrating myinvention, and Fig; 2 is a cross-sectional elevation thereof.

Referring-to the drawings and in detail, A designates the reciprocatingbed or member which is mounted in the usual way so as to reciprocate onthe frame of the machine.

B designates the impression cylinder and 10 designates a ower shaft towhich power may be applied om any suitable source by 'drive theimpression cylinder by meshing with a large gear 15 secured thereon. The

relation between the gears 13 and 15 is such that the driving shaft 14makes three revolutions for each two revolutions of the impressioncylinder the mechanism being illustrated as applied to the ordinarytwo-revolution impression cylinder printing machine having athree-revolution driving shaft or movement.

Secured to the bed are upper and lower racks 16 and 17. The inner end ofthe shaft 14 is journaled in a strong bracket 18. On the end of theshaft 14 is arranged a large Wide-faced gear 19 which is dis osedbetween the racks 16 and 17, the rac (s 16 and 17 being set so as tojust clear said gear.

Loosely fitted on said stud 20 is an intermediate gear 21 which ishereinafter termed the upper intermediate. This gear is set to mesh withthe gear 19 and the upper surface of the same comes above the uppersurface of the gear 19 in position to engage the upper rack 16. Alsosecured in the bracket 18 is a stud 22. Arranged on the same similarlyto the upper intermediate 21 is a lower intermediate 23 which is set inposition to engage the lower rack 17 A lever 24 is pivoted on a stud 25j ournaled in an arm projecting from the bracket 18. This lever hashooks 26 which engage the sides of the upper intermediate 21 and hooks2727 which engage the sides of the lower intermediate 23. By thisarrangement, when one intermediate is moved into the plane of the racks16 and 17, the other intermediate will be moved out of positionlaterally to clear its rack.

28 designates a cam shaft. This cam shaft is driven bya pinion 29secured on the driving shaft 14 which meshes with a gear 30 secured onthe cam shaft 28; the reduction between the pinion 29 and the gear 30being three to one so that the cam shaft 28 will make one revolution foreach complete operation of the machine. Secured on the cam shaft 28 is acam 31. A lever 32 is mounted on a stud 33 and carries a roller 34 whichen-- gages the groove of the cam 31. The lever 32 is connected by a link35 to the lower end of the rocking lever 24.

-stud 20 is rigidly secured in said bracket 18.

The gear 19 is made of the usual size; that is, if the improvement isapplied to a threerevolution movement as shown, the circumference ofsaid gear represents the length of the constant speed forward andbackward movements. A wrist-pin 36 may be set on said gear and mayoperate the usual yoke 37 from which the reversing movement is obtained,the details of which reversing movement are not described herein as theymay be of any improved type and form no part of the present invention.

In operation, the upper intermediate 21 engages the u per rack 16 forthe return movement of t e bed and the lower intermediate 23 engages thelower rack 17 for the forward or printing movement of the bed. Theintermediates are shifted during the reversing movement. This shift,takes place when no part of the work is being performed by the maindriving mechanism and can be easily accomplished without wear. By thisarrangement, thegear 19 is rigidly supported and each intermediate whenit comes into operation, is working close up to the bearing of itssupporting stud. By this arrangement astrong, simple, accurately workingmain driving mechanism is provided.

The details and arrangements herein described may be greatly varied by askilled mechanic without departing from the scope of my invention asexpressed in the claims.

Having thus fully described my invention, What I claim and desire tosecure by Letters- Patent of the United States is 1. In a mechanicalmovement, a main driving mechanism comprising upper and lower racks, agear arranged between the same of less diameter than the dlstancebetween the racks, two intermediates, and

means for bringing the intermediates alternately into operation.

2. In a mechanical movement, a main driving mechanism comprising upperand lower racks, a gear arranged between the same of less diameter thanthe distance between the racks, two intermediates, and means for slidingthe same axially to cooperate with said racks.

3. In a mechanical movement, a main driving mechanism comprising upperand lower racks arranged in the same plane, a gear having a face widerthan said racks and of less diameter than the distance between theracks, two intermediates continuously meshing with said gear, and meansfor sliding the intermediates axially in opposition.

4. In a mechanical movement, a main driving mechanism comprising upperand lower racks, a wide-faced gear arranged between the same of lessdiameter than the distance between the racks, studs secured to theframe, intermediates journaled on said. studs, and means for bringingthe intermediates into operation alternately.

In testimony whereof I have hereunto set my hand, in the presence of twosubscribing witnesses.

. ROBERT T. JOHNSTON. Witnesses:

CHARLES EVERETT MOORE, RosA C. ONEIL.

